Great Mosque of Xi'an - Islam came to China fairly early in its history, by the late 7th century for sure. The Great Mosque of Xi'an is China's oldest standing mosque and still one of its most significant. Although founded in 742 (it was built during the reign of Li Longji - see below), it has been upgraded several times. It's current structure was mostly built during the Ming Dynasty. Perhaps its most interesting feature is that, despite being a Muslim temple, the architecture is exclusively Chinese (apart from a few Arabic letters and decorations on the interior).